The present invention relates to a quick safety connection for the removable joining of pipes and, more specifically, to a so-called xe2x80x9cdouble-releasexe2x80x9d quick connection.
European Patent Application 0 722 063 discloses a double-release quick connection in which two rings are used, provided with elastic claw elements adapted to cooperate successively with an outer groove of a male connector in order to release this connector in two steps, allowing the discharge of the fluid contained in the downstream pipe, which avoids the whiplash movements which might prove dangerous for a user with a single-release connection. Other double-release connections are known for example from U.S. Pat. No. 5,290,009 or DE-A-27 41 512.
In these known devices, an outer ring or sleeve is used for controlling, on the one hand, means for locking the male connector in the female element in a position of communication of the pipes, and, on the other hand, members for retaining the connector in intermediate position of emptying or discharge of the downstream pipe. In this position of discharge, the fluid which flows from the male connector fills the inner volume of the sleeve, which has the effect of increasing the pressure prevailing in an annular chamber defined around the body of the female element and inside this sleeve. Such increase in pressure may, in at least certain configurations, induce a displacement of the sleeve corresponding to an increase in the volume of this chamber, i.e. to a reduction of this pressure. Such a displacement may have the consequence of releasing the male connector without the intervention of an operator, which may result in a violent discharge and a potentially dangerous xe2x80x9cwhiplashxe2x80x9d.
It is a particular object of the present invention to overcome these drawbacks by proposing a quick safety connection in which the male connector does not risk passing automatically, i.e. without the intervention of the operator, from its position of locking in the female element to a position of complete disconnection, without retention in its position of discharge of the downstream pipe.
To that end, the invention relates to a quick connection of the type mentioned hereinbefore, which comprises means for limiting the movement of the sleeve, under the effect of the pressure prevailing in its inner volume due to the discharge of the pipe in the intermediate position, towards a position of release of the connector by the retention member.
Thanks to these means for limiting the movement of the sleeve, the latter cannot be displaced towards a position of release, premature and automatic, of the male connector.
According to a first advantageous embodiment of the invention, the means for limiting the movement of the sleeve comprise venting orifices allowing the flow of the fluid issuing from the downstream pipe, from the inner volume of the sleeve towards the outside of the connection. These vents avoid too great a rise in pressure within the sleeve, particularly in an annular chamber defined around the body of the female element. Such a pressure is therefore not capable of inducing an untimely displacement of the sleeve. The venting orifices advantageously present a total cross-section allowing the flow of the fluid issuing from this downstream pipe without substantial rise in the pressure in the inner volume of the sleeve.
According to a second, particularly advantageous embodiment of the invention, the means for limiting the movement of the sleeve comprise a stop adapted to cooperate with an inner heel of the sleeve, this stop being disposed in the inner volume of the sleeve. Such a stop makes it possible efficiently to limit the movements of the sleeve. According to an advantageous aspect, the stop is formed by a ring disposed around the body of the female element in an annular chamber defined between the body and the sleeve. This ring may be provided to be elastically loaded in the direction of an outer bearing surface of the body and in the direction of the heel of the sleeve. In that case, the means for elastically loading the ring may be formed by means for elastic return of the sleeve into position of engagement of the locking mechanism and/or of the retention member.
According to another advantageous aspect of the invention, the clearance between the body of the female element and the sleeve, downstream of the stop in the direction of flow of the fluid, in the intermediate position of the connector, is greater than the clearance between this stop and the body and/or than the clearance between this stop and this sleeve. This aspect of the invention guarantees that the pressure downstream of the stop is permanently lower than the pressure upstream of this stop, with the result that the stop is permanently subjected to a difference in pressure which tends to apply it towards the bearing surface defined on the body and towards the heel of the sleeve.
The known devices comprise means for locking in transfer position and means for retention in intermediate position, adapted to cooperate with a particular geometry of connector, particularly in the case of using elastic claws. Now, the connectors that may be used with the female elements may have several origins and variable geometries, with the result that the locking means and/or the manoeuvring members are not always fully efficient. In order to overcome this drawback, the retention member is formed by a ball capable of axial and radial movements in an oblong slot formed in the body. Furthermore, the locking mechanism may comprise needles mobile in oblong slots formed in the body in directions inclined with respect to the direction of introduction and of extraction of the male connector in and from the female element.